/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.aliyun.odps.graph.local.message;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.io.FileUtils;

import com.aliyun.odps.io.Writable;

public class MsgBuffer {

  private List<Writable> msges;

  public MsgBuffer() {
    msges = new ArrayList<Writable>();
  }

  public void addMessage(Writable msg) {
    synchronized (msges) {
      msges.add(msg);
    }
  }

  public boolean hasMessages() {
    synchronized (msges) {
      return msges.size() > 0;
    }
  }

  public List<Writable> getMessages() {
    synchronized (msges) {
      return msges;
    }
  }

  public void dump(File out) throws IOException {
    synchronized (msges) {
      FileUtils.writeLines(out, msges);
    }
  }

}
